Self-locking core chucks

Abstract

A core chuck designed to lock the core of a roll of material winding and unwinding operations to a mandrel, which core chuck comprises a core and a tubiform cylindrical chuck body dimensioned to accommodate the core. Means are provided for fastening the chuck body onto the mandrel shaft. The chuck body defines on the surface opposite the core at least one recess disposed parallel to the rotating axis thereof which recess has a releasably terraced bottom step plate including at least one step ascending from a common center groove to each side of the recess. The top faces of the step and of the common center groove are substantially parallel to and spaced apart at different distances from the opposite smooth face of the core. At least one toothed roller is disposed in the recess with its axis parallel to the axis of the chuck body. The top face of each of the steps has two raised ribs spaced apart from each other to define an axially disposed groove therebetween, and receives the corresponding tooth of the toothed roller, in order to prevent an axial movement and an inclined position of the latter. Retaining means are provided to prevent the overextension of the springs, as well as the outward movement of the locking roller and of the step plate. The retaining means may include an arch shaped stamping which is inserted with slight pressure at each end of the roller recess, to form a cover or roof, both legs of the arch shaped stamping resting on the top side of the step plate. The toothed roller has an extended pin on each end and said extended pin is disposed spaced apart from the bottom face of said stamping upon locking the same in said core.

I claim: 
     
       1. A core chuck designed to lock the core of a roll of material winding and unwinding operations to a mandrel, said core chuck comprising a core, a tubiform cylindrical chuck body dimensioned to accommodate said core,   means for fastening said chuck body onto a mandrel shaft,   said chuck body defining on the surface opposite said core at least one recess disposed parallel to the rotating axis thereof,   said recess having a terraced bottom step plate including at least one step ascending from a common center groove to each side of said recess,   the top faces of said step and of said common center groove being substantially parallel to and spaced apart at different distances from the opposite smooth face of said core,   at least one toothed roller disposed in said recess with its axis parallel to the axis of said chuck body,   the top face of each of said steps having two raised ribs spaced apart from each other to define an axially disposed groove therebetween, and receiving the corresponding tooth of said toothed roller, in order to prevent an axial movement and an inclined position of the latter,   said toothed roller having an outer diameter slightly in excess of the greatest depth of said recess with one tooth resting on the bottom of said center groove and an opposing tooth adapted to bite into the opposite face of said core to form a pivot point for a turning of said roller,   a tooth adjacent to said one tooth adapted to mount said step adjacent said common center groove and to enter said grooves between said raised ribs in response to a lateral force acting upon at least said opposing tooth of said toothed roller,   resilient means engaging said toothed roller to return said roller into the lowermost position in said recess upon cessation of said lateral force,   retaining means to prevent the over-extension of said resilient means and the outward movement of said toothed roller and of said plate, and   said retaining means including a substantially arch shaped stamping resting on the top face of said step plate and being enclosed by steel bands.   
     
     
       2. A core chuck designed to lock the core of a roll of material winding and unwinding operations to a mandrel, said core chuck comprising 
     
     
       a core, a tubiform cylindrical chuck body dimensioned to accommodate said core, means for fastening said chuck body onto a mandrel shaft,   said chuck body defining on the surface opposite said core at least one recess disposed parallel to the rotating axis thereof,   said recess having a terraced bottom step plate including at least one step ascending from a common center groove to each side of said recess,   the top faces of said step and of said common center groove being substantially parallel to and spaced apart at different distances from the opposite smooth face of said core,   at least one toothed roller disposed in said recess with its axis parallel to the axis of said chuck body,   the top face of each of said steps having two raised ribs spaced apart from each other to define an axially disposed groove therebetween, and receiving the corresponding tooth of said toothed roller, in order to prevent an axial movement and an inclined position of the latter,   said toothed roller having an outer diameter slightly in excess of the greatest depth of said recess with one tooth resting on the bottom of said center groove and an opposing tooth adapted to bite into the opposite face of said core to form a pivot point for a turning of said roller,   a tooth adjacent to said one tooth adapted to mount said step adjacent said common center groove and to enter said grooves between said raised ribs in response to a lateral force acting upon at least said opposing tooth of said toothed roller,   resilient means engaging said toothed roller to return said roller into the lowermost position in said recess upon cessation of said lateral force,   retaining means to prevent the over-extension of said resilient means and the outward movement of said toothed roller and of said plate, and   said retaining means including a substantially arch shaped stamping resting on the top face of said step plate and being enclosed by wire rings, and   said toothed roller having an extended pin on each end and said extended pin being disposed spaced apart from the bottom face of said stamping upon locking the same in said core.